Pregnancy in a healthy woman with untreated citrullinemia

We report the clinical and biochemical data on a second successful pregnancy in a woman with citrullinemia due to argininosuccinate synthetase deficiency (CTLN1). Despite very elevated plasma and urine citrulline and little or no measurable argininosuccinate synthetase enzyme activity on cultured skin fibroblasts, this 29-year-old woman, who was identified through newborn screening, has remained asymptomatic throughout her life. Mutation …